“The heavenly phænomena do not inspire those who give different explanations of them, conformable with appearances, instead of explaining them by hypothesis, with any alarm. But if, abandoning hypothesis, one at the same time renounces the attempt to explain them by means of analogies founded on appearances, then one is placing one’s self altogether at a distance from the science of nature, in order to fall into fables.
“It is possible that the heavenly phænomena may present some apparent characters which appear to assimilate them to those phænomena which we see taking place around ourselves, without there being any real analogy at the bottom. For the heavenly phænomena may depend for their production on many different causes; nevertheless, we must observe the appearances presented by each, and we must distinguish the different circumstances which attach to them, and which can be explained in different manners by means of analogous phænomena which arise under our eyes.
“The world is a collection of things embraced by the heaven, containing the stars, the earth, and all visible objects. This collection, separated from the infinite, is terminated by an extremity, which is either rare, or dense, or revolving, or in a state of repose, or of a round, or triangular, or of some shape or other in fact, for it may be of any shape, the dissolution of which must bring the destruction of everything which they embrace. In fact, it can take place in every sort of way, since there is not one of those things which are seen which testifies against this world in which we cannot detect any extremity; and that such worlds are infinite in number is easily seen, and also that such a world can exist both in the world and in the μετακόσμιον, as we call the space between the worlds, being a huge space made up of plenum and vacuum, but not, as some philosophers pretend, an immensity of space absolutely empty. This production of a world may be explained thus: seeds suitably appropriated to such an end may emanate either from one or from several worlds, or from the space that separates them; they flow towards a particular point where they become collected together and organized; after that, other germs come to unite them together in such a way as to form a durable whole, a basis, a nucleus to which all successive additions unite themselves.
“One must not content one’s self in this question with saying, as one of the natural philosophers has done, that there is a re-union of the elements, or a violent motion in the vacuum under the influence of necessity, and that the body which is thus produced increases until it comes to crash against some other; for this doctrine is contrary to appearances.
“The sun, the moon, and the other stars, were originally formed separately, and were afterwards comprehended in the entire total of the world. All the other objects which our world comprises, for instance, the earth and the sea, were also formed spontaneously, and subsequently gained size by the addition and violent movement of light substances, composed of elements of fire and air, or even of these two principles at once. This explanation, moreover, is in accordance with the impressions of the senses.
“As to the magnitude of the sun and of the other stars, it is as far as we are concerned, such as it appears to us to be.”
(This same doctrine is reproduced, and occurs again in the eleventh book of his treatise on Nature; where he says, “If the distance has made it lose its size, à fortiori, it would take away its brilliancy; for colour has not, any more than size, the property of traversing distance without alteration.”)
“But, considered by itself, the sun may be a little greater or a little smaller than it appears; or it may be just such as it looks; for that is exactly the case with the fires of common occurrence among men, which are perceived by the senses at a distance. Besides, all the difficulties on this subject will be easily explained if one attends to the clear evidence of the perceptions, as I have shown in my books about Nature.
“The rising and setting of the sun, of the moon, and of the stars, may depend on the fact of their becoming lighted up, and extinguished alternately, and in the order which we behold. One may also give other reasons for this phænomenon, which are not contradicted by any sensible appearances; accordingly, one might explain them by the passage of the stars above and below the earth, for the impressions of the senses agree also with this supposition.
“As to their motion, one may make that depend on the circular movement of the entire heaven. One may also suppose that the stars move, while the heaven itself is immoveable; for there is nothing to prevent the idea that originally, before the formation of the world, they may have received, by the appointment of fate, an impulse from east to west, and that now their movement continues in consequence of their heat, as the fire naturally proceeds onwards in order to seek the aliment which suits it.